The purpose of this study was to examine how a student's college academic success at Iowa State University (ISU) is related to college credit earning while in high school. The unit of analysis for this research was first time full time first year students who entered ISU in the fall semester of 2006, 2007, and 2008. This study examined the relationships between students' college credit earning while in high school, background attributes such as high school grade point average (GPA) and/or ACT/SAT scores, and their college academic success as measured by GPA and persistence to the second fall. The types of college prep courses taken were also examined, for example college credits earned versus no college credits earned and Advanced Placement (AP) credits versus two-year college credits.

The first year students' first semester college GPA were regressed on four variables associated with high school preparation for college (high school GPA, ACT score, sum of credits earned while in high school, and type of credits earned while in high school. High school GPA, ACT score, and sum of college credits earned while in high school accounted for 32.8% of the variation in first semester college GPA.

A logistic regression was performed with high school GPA, ACT score, number and type of college credits earned while in high school as the independent variables, and the persistence to the second fall as the dichotomous dependent variable. Increases in high school GPA, ACT score, and number and type of college credits earned while in high school increased the likelihood of students returning for a second fall semester.

The findings of this study provide evidence to K-12 and community college administrators, high school counselors, parents and high school students. These findings suggest that college credit earning while in high school does increase college academic success as measured by first semester GPA and persistence to the second fall term.